public byte[] Encrypt(byte[] data, int offset, int length)
{
using var buffer = new MemoryStream(255);
using var writer = new BinaryWriter(buffer);
using (var sha1 = new SHA1Managed())
{
var hashsum = sha1.ComputeHash(data, offset, length);
writer.Write(hashsum);
}
buffer.Write(data, offset, length);
if (length < 235)
{
var padding = Helpers.GenerateRandomBytes(235 - length);
buffer.Write(padding, 0, padding.Length);
}
var ciphertext = new BigInteger(1, buffer.ToArray()).ModPow(Exponent, Modulus).ToByteArrayUnsigned();
if (ciphertext.Length == 256)
{
return(ciphertext);
}
var paddedCiphertext = new byte[256];
var paddingLength = 256 - ciphertext.Length;
for (var i = 0; i < paddingLength; i++)
{
paddedCiphertext[i] = 0;
}
ciphertext.CopyTo(paddedCiphertext, paddingLength);
return(paddedCiphertext);
}
public void WriteDecimal(decimal value, int scale, int len)
{
var bytes = new BigInteger(value * (long)Math.Pow(10, scale)).ToByteArray(isBigEndian: true);
var fix = new byte[len];
var offset = len - bytes.Length;
if (value < 0)
{
Array.Fill(fix, (byte)0xFF, 0, offset);
}
bytes.CopyTo(fix, offset);
WriteFixed(fix);
}
public byte[] Encrypt(byte[] data, int offset, int length)
{
logger.debug("rsa plaintext: {0}", BitConverter.ToString(data, offset, length));
using (MemoryStream buffer = new MemoryStream(255))
using (BinaryWriter writer = new BinaryWriter(buffer)) {
using (SHA1 sha1 = new SHA1Managed()) {
byte[] hashsum = sha1.ComputeHash(data, offset, length);
logger.debug("hashsum: {0}", BitConverter.ToString(hashsum));
writer.Write(hashsum);
}
buffer.Write(data, offset, length);
if (length < 235)
{
byte[] padding = new byte[235 - length];
new Random().NextBytes(padding);
buffer.Write(padding, 0, padding.Length);
}
logger.debug("rsa plaintext with hashsum and padding: {0}", BitConverter.ToString(buffer.ToArray()));
byte[] ciphertext = new BigInteger(1, buffer.ToArray()).ModPow(e, m).ToByteArrayUnsigned();
logger.debug("ciphertext length: {0}, ciphertext: {1}", ciphertext.Length, BitConverter.ToString(ciphertext));
if (ciphertext.Length == 256)
{
return(ciphertext);
}
else
{
byte[] paddedCiphertext = new byte[256];
int padding = 256 - ciphertext.Length;
for (int i = 0; i < padding; i++)
{
paddedCiphertext[i] = 0;
}
ciphertext.CopyTo(paddedCiphertext, padding);
logger.debug("ciphertext with padding: {0}", BitConverter.ToString(paddedCiphertext));
return(paddedCiphertext);
}
}
}
public byte[] Encrypt(byte[] data, int offset, int length)
{
using (var buffer = new MemoryStream(255))
using (var writer = new BinaryWriter(buffer))
{
using (var sha1 = SHA1.Create())
{
var hashsum = sha1.ComputeHash(data, offset, length);
writer.Write(hashsum);
}
buffer.Write(data, offset, length);
if (length < 235)
{
var padding = new byte[235 - length];
// new Random().NextBytes(padding);
buffer.Write(padding, 0, padding.Length);
}
var ciphertext = new BigInteger(1, buffer.ToArray()).ModPow(_e, _m).ToByteArrayUnsigned();
if (ciphertext.Length == 256)
{
return(ciphertext);
}
{
var paddedCiphertext = new byte[256];
var padding = 256 - ciphertext.Length;
for (var i = 0; i < padding; i++)
{
paddedCiphertext[i] = 0;
}
ciphertext.CopyTo(paddedCiphertext, padding);
return(paddedCiphertext);
}
}
}
public byte[] Encrypt(byte[] data, int offset, int length)
{
using (MemoryStream buffer = new MemoryStream(255))
using (BinaryWriter writer = new BinaryWriter(buffer))
{
using (SHA1 sha1 = new SHA1Managed())
{
byte[] hashsum = sha1.ComputeHash(data, offset, length);
writer.Write(hashsum);
}
buffer.Write(data, offset, length);
if (length < 235)
{
byte[] padding = new byte[235 - length];
new Random().NextBytes(padding);
buffer.Write(padding, 0, padding.Length);
}
byte[] ciphertext = new BigInteger(1, buffer.ToArray()).ModPow(this.e, this.m).ToByteArrayUnsigned();
if (ciphertext.Length == 256)
{
return(ciphertext);
}
else
{
byte[] paddedCiphertext = new byte[256];
int padding = 256 - ciphertext.Length;
for (int i = 0; i < padding; i++)
{
paddedCiphertext[i] = 0;
}
ciphertext.CopyTo(paddedCiphertext, padding);
return(paddedCiphertext);
}
}
}
